Lever doorknob adaptor



FIG. 1 is a front, top and right perspective view of a lever doorknob adaptor showing my new design, the broken line showing of a doorknob being for illustrative purposes only;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a right side elevational view thereof; and,

FIG. 7 is a left side elevational view thereof. 

The ornamental design for a lever doorknob adaptor, as shown and described. 